cxgb3: avoid potential memory leak.

Add consistency in alloc_ring() parameter checking
to avoid potential memory leaks.
alloc_ring() callers are correct fo far.

Signed-off-by: Divy Le Ray <divy@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/cxgb3/sge.c b/drivers/net/cxgb3/sge.c
index 268f158..bc6a8dc 100644
--- a/drivers/net/cxgb3/sge.c
+++ b/drivers/net/cxgb3/sge.c
@@ -549,16 +549,15 @@
 
 	if (!p)
 		return NULL;
-	if (sw_size) {
+	if (sw_size && metadata) {
 		s = kcalloc(nelem, sw_size, GFP_KERNEL);
 
 		if (!s) {
 			dma_free_coherent(&pdev->dev, len, p, *phys);
 			return NULL;
 		}
-	}
-	if (metadata)
 		*(void **)metadata = s;
+	}
 	memset(p, 0, len);
 	return p;
 }